Fire control instrument



' VV? )L flu Dec. l2, 1933. www. H. c. FORD FIRE CONTROL INSTRUMENT Filed Feb. 18, 1928 2 Sheets-Sheet 1 N l JNVENToR. 6B MNA/[BAL ara/w N BY D /W /TORNEYS l Dem 12, 1933. H. C. FORD 1,938,825

FIRE CONTROL INSTRUMENT Filed Feb. 18, 1928 2 Sheets-Sheet 2 f TORNEYS.

Patented Dec. 12, 1933 UNITED STATES PATENT OFFlCE FIRE CONTROL INSTRUMENT Application February 18, 1928. Serial No. 255,245

20 Claims.

This invention relates to a fire control instrument particularly adapted for use in systems in which guns are controlled from a director station. A system of this general character is disclosed in my copending United States application Serial No. 744,051, filed October 16, 1924, and granted July 7, 1931 as Patent No. 1,813,534.

At the present time it is customary to control the training and elevating of the guns of warships, except possibly those of small caliber, from fire control stations provided with instruments called directors from which indications of the train and elevation required for the guns are sent by suitable signal transmission systems. As the guns are located at different points on the ship their distances and bearings from the director station are diiferent and their lines of fire with respect to the line of sight at the director also vary, thus introducing errors, known as parallax errors, which are also affected by changes in range of the target. The angle of elevation of the line of fire is likewise affected by errors resulting from parallax and other causes. The direction and amount of gun train and gun elevation transmitted from the director station are therefore not in general correct for any particular gun and means must be provided for entering the proper corrections in the receivers at the different guns.

Directions for elevation usually in minutes of arc are also transmitted from the director station to each gun. The necessary elevation of a gun when aimed at a target depends upon the range and the erosion factor resulting from the number of rounds fired and corrections for these factors must be applied to the indications received from the director station. Provisions for making such corrections are disclosed in said patent which shows an erosion and parallax adjuster containing not only members for manual operation and scales for reading range and rounds fired, but also mechanism relating this data and producing output suitable to feed to the train and elevation repeat backs respectively.

For after guns on certain vessels, mechanism is required to compensate for the range component of horizontal parallax. This range component arises from the fact that there is a considerable distance between the after gun and the director station and the elevation determined at the director would be too great for any such gun when the latter is trained astern and too small when the gun is trained forward, the elevation at the gun and at the director station being the same when the two lines of sight make equal angles with the base line joining the gun position and (Cl. 23S-61.5)

the director station. Similar conditions arise in the case of forward guns controlled by an after director.

Some of the objects of the present invention are to provide at the guns improved receiver instruments in which angle readings are set up from a director station and which are returned to zero readings by movement of the guns to the proper positions; receiver instruments settable from director stations and in which certain indications are changed to zero by positioning the guns as directed and other indications are changed to indicate the angles made by the guns with certain reference directions; means for generating corrections in elevation to compensate for range components of horizontal parallax and for changing the elevation indications accordingly; means to adjust the elevation indications includ-- ing means for generating erosion corrections, corrections to compensate for the range component of horizontal parallax, and range functions, and means for combining the erosion and parallax functions and multiplying them by the range function; and means acting on the range connection between an adjuster and an indicator to render the connection effective below a certain range setting and ineffective above such range setting.

Among other features and advantages of the invention are the following:

1. Due to the generation of certain corrections in the indicator instruments instead of at the erosion and parallax adjusters there is a reduction in the quantity of mechanism involved with a consequent reduction in the cost of manufacture and an increase in reliability;

2. There are only two shafts, and these are directly hand driven, connecting the erosion and parallax adjuster with the elevation indicator, instead f three as would be necessary in case the range component of horizontal parallax were transmitted from the erosion and parallax adjuster.

3. The erosion and parallax adjusters are interchangeable for all locations of the guns, that is to say, there is no difference in the instruments at guns where a correction for the vertical component of parallax is required and at guns where no such correction is required. It should also be observed that elevation indicators are interchangeable in that by locking certain means out of action the correction for the vertical component of parallax may be eliminated.

With these and other objects in View the invention consists of the construction and combinations which will be hereinafter set forth and earch titan will be particularly pointed out in the appended claims.

In the drawings:

Fig. 1 is a schematic View of an elevation indicator; and

Fig. 2 is a schematic view of an erosion and parallax adjuster for connection with an elevation indicator, and means for automatic connection and disconnection of the range function connection.

The gun elevation indicator 1 is mounted in the after enclosed gun mount in such a position that the coarse and fine Zero-reading dials 2, and 3, respectively, and the coarse and ne anglereading dials 4 and 5, respectively may readily be seen by the gun pointer. The indicator is connected by means to be described hereinafter with auxiliary elevation and training racks 6 and 7 respectively and with an erosion and parallax adjuster indicated generally by 8.

The function of the instrument 1 is to indicate by the zero-reading dials 2 and 3 when the gun has been elevated to the required angle and to indicate by the coarse and fine angle-reading dials 4 and 5 the angle at which the gun is elevated, minus the algebraic sum of range compensation for horizontal parallax and compensations for gun erosion and roller path inclination, these three quantities being generated within the instrument.

The zero reading dials 2 and 3 are connected respectively with rotors 9 and 10 of selsyn motors 11 and 12 having statcrs 13 and 14 in which different conditions are set up by selsyn generators at a director station, not shown, to set the rero reading dials in accordance with the elevation observed at the director station. As the operator changes the elevation of the gun, the stators 13 and 14 are turned in the direction opposite to that in which the rotors were displaced.

To transmit the changes in elevation of the gun to the dials, use is made of the auxiliary elevation rack 6 on the gun mount and meshing with an elevation pinion 16 fixed on the end of a main drive shaft 17. This shaft carries on its other end a bevel gear 19 which through a bevel gear 20 drives the elevation drive shaft 21 which enters the indicator 1 through the bottom of the case.

The elevation drive shaft 21 is connected through a coupling 22 to an elevation shaft 23 carrying at its upper end a gear 24 which through a gear 25 and hollow shaft 26 turns the lower gear 27 of a dial differential 28 to a position to represent the actual elevation of the gun. 'Ihe dial diiferential also includes a spider 29, carrying two small gears 30 in mesh with each other and one of which meshes with the gear 27 and the other with a gear 31. The spider 29 is mounted on a shaft 32 through which corrections are introduced by means to be described hereinafter and the gear 31 serves to transmit the resultant movement.

Extending upwardly from the gear 31 is a shaft 33 carrying at its upper end a gear 34 meshingv with a gear 35 on the stator 14 of the fine selsyn motor 12 and with a gear 36 on a shaft 37 carrying at its upper end the fine angle-reading dial 5 and at another point a gear 38. The last mentioned gear acts through gears 39, 40 and 4l and shaft 42 to turn a gear 43 which through a gear 44 turns the coarse angle-reading dial 4 and through a gear 45 turns the stator 13 of the selsyn motor 11.

The instrument receives a function of the range from shaft 46 outside the case and mechanically connected with a range drum of the erosion and parallax adjuster 8. Mounted on the shaft 46 is a spur gear 47, a left hand worm 48 and a clutch member 49. Driven by gear 47 and worm 48 respectively are high and low speed locking discs 50 and 51 respectively of a stop mechanism which prevents the range carriage setting mechanism, to be described hereinafter in the indicator 1 from being turned beyond a predetermined range position, in this case the 20,000 yard range position, but at the same time allows the erosion and parallax adjuster to continue operation up to the infinity range setting. The operation of the stop mechanism is as follows:

Gear 47 drives the high speed locking disc 50 through gears 52 and 53, shaft 54, bevel gears 55, and shaft 56. The left hand worm 48 drives through gears 57 and 58 the low speed locking disc 51 which is loose on shaft 56. These locking discs revolve in opposite directions and each is provided with a slot 59 in its periphery. As the discs 50 and 51 turn, a single tooth 60 of a locking member or pinion 6l bears on the edges of the discs, until the 20,000 yard position of the range carriage is reached, when the tooth 60 of the locking pinion 61 is forced into both slots 59, by a spring 62 attached at one end to an arm 63 fixed on a shaft 64 on which said pinion 61 is xed.

Fixed on the shaft 64 is an arm 65 and pivoted thereto is a block 66 between two clutch arms 67 pivoted at 68 and drawn together by means of a centralizing spring 69. When the tooth 60 drops into the slots or notches, the block 66 presses against the outer arm 67 and by means of the spring 69 swings the other arm 67 to cause a fork 70 thereon to withdraw the clutch member 49 on the shaft 46 from effective engagement with the clutch member 72 on a shaft 73 and cause a tooth 74 on the same clutch arm 67 to enter a notch or slot 75 in the clutch member 72 to lock the shaft 73 against turning. Upon continuing the turning of the range shaft 46 above 20,000 yards, the tooth 60 of the locking pinion 61 is forced by the side of the slot 59 in the high speed locking disc 50 out of the slot in the low speed locking disc 51 and along the edges of the discs but turned in the opposite direction. This movement of the locking pinion causes the block 66 to be moved still farther and to stretch the spring 69 to a greater extent, the clutch being kept open and the clutch member 72 locked. On passing from the higher ranges through the 20,000 yard position to the lower ranges, the sequence of operations is reversed.

The clutch shaft 73 drives the bevel gears 76 and the range drive shaft 77 from which motion is transmitted to the range shaft 78 by connections including bevel gears 79 and spur gears 80. Shaft 78 extends to a window at the right hand side of the case where through a planetary system 81 it drives a slowly moving or coarse dial 82 and a fine dial 83, each dial carrying an index mark which indicates the zero setting for range when the two marks are in line with a fixed pointer 84.

Fixed on the range shaft 78 is a worm 85 engaging a worm gear 86 which drives a cam plate 87 through a stud 88 projecting from the worm gear 86, and a roller 89 in a groove 90 in the cam plate 87. In practice the cam plate 87 is formed with a cam in the lower face thereof but for clearness they are here shown as two parts 87 and 91 held together by driving pins 92. The centers of the cam plate 87 and the worm gear 86 are offset to improve the curve of the cam which is designed to drive mechanism to be described hereinafter.

To prevent the worm gear 86 from being turned beyond the zero and the 20,000 yard range position when the instrument is out of the case or before the external stop mechanism has been attached, provision is made of a stop mechanism connected with the range shaft 78. Such stop mechanism consists of a stop nut 93 which is driven by a threaded portion of the range shaft along a guide rail 94 until one of two pins 95 on opposite sides of the nut comes into contact with the corresponding stop pin 96 on the shaft. This construction permits the erosion compensation and range compensation for horizontal parallax to vary with the range from 1,000 to 20,000 yards and to remain constant for ranges exceeding 20,000 yards.

The cam 91 upon movement thereof drives a cam follower 97 mounted on one end of a cornpound lever 98 having at its other end a stud 99 with a roller 100 movable in a guideway in a range carriage 101. The range carriage is slidably mounted as by guide rails 102 and carries a stud 103 provided with a roller 104 which enters a slot in and serves as a fulcrum for an arm 105. The purpose of the mechanism between the worm gear 86 and the range carriage 101 is tofmodify the function of range received from the erosion and parallax adjuster 8 to give the desired function at the range carriage. The instrument receives a function of erosion compensation from shaft 105' mechanically connected with the erosion compensation element of the erosion and parallax adjuster 8. The shaft 105 through bevel gears 106 drives a rounds fired drive shaft 107 which through the bevel gears 108 drives the rounds fired shaft 109. To prevent the rounds fired shaft from being turned beyondy the maximum and minimum limits of travel, the shaft is threaded for a short length and carries a nut 110 having projections 111 on opposite sides thereof which, as the nut approaches the limit of its travel along the guide 112 engages stops 113 on the shaft. Shaft 109 extends to a window at the side of the case where a planetary system 114 drives a slowly moving or coarse dial 115 and a ne dial 116. Each of these dials carries an index mark and the index marks when brought into line with the fixed pointer 117 indicate the zero setting of the erosion compensation mechanism. Fixed on the shaft 109 is a worm 118 meshing with a worm wheel 119 on a shaft 120 carrying at its lower end a gear 121 forming part of a differential 122. The gear 121 together with a gear 123 having connections to be described hereinafter drive a spider 124 xed to a shaft 125 having at its upper end a gear 126 from which is driven a rack 127 mounted on a rounds fired and parallax carriage 128 slidably mounted on guide rails 129. The carriage 128 carries a stud 130 movable in a slot in one end of the compensation arm 105.

The training of the gun drives a spur gear 131 around the stationary auxiliary training rack 7 and causes shaft 132 and gear 133 to turn gear 144 for driving the training shaft 145. At its upper end shaft 145 carries a gear 146 to drive a training angle gear 147, the gear ratios being such that the training angle gear is rotated at a one to one ratio with the training of the gun. The gear 147 carries an azimuth scale 148 which may be read against pointer 149 to indicate the angle at which the gun is trained.

The roller path compensation is generated by a crank pin 150 rotated by the training angle gear 147, the crank pin 150 being mounted in a block 151 whose radial distance from the center of gear 147 represents the maximum roller path inclination and is adjusted by thelroller path setting screw 152. The screw 152 carries a gear 153 meshing with a crown gear 154 on the roller path inclination scale 155. In making the setting for roller path inclination the scale 155 is rotated and read against an index line on the disc 156 and the setting is locked by tightening screw 157 which clamps a scale 158 against a shoulder of the scale 155.

The training of the gun from the high point of the roller path is shown by the scale 158 read against a pointer 159. Shifting this scale changes the position of the crank pin 150 and its supporting mechanism with respect to the training angle gear 147. This setting is locked by screws 160. The pin 150 is always displaced 90 degrees from the angle read on the scale 158 so that the quantity generated by the rotation of the pin is a function of the sine of the angle shown on the scale. This is the desired function for generating the roller path compensation. Training gear scale 148 which is read against the pointer 149'indicates the existing training of the gun.

The crank pin 150 drives a roller 160 thus moving a roller path carriage 161 in guide rails 162 and the roller path carriage in turn adjusts the position of a rack 163 for the roller path compensation. This rack also receives an adjustment from a worm 164 in a manner to be described hereinafter and drives a gear 165 to turn through a shaft 166, a gear 167 forming part of a compensation differential indicated in general by 168.

The range compensation for horizontal parallax is divided into two components, designated for convenient reference as A and B, of which' the rst A varies with the train of the gun and with the range, and the second component B varies only with the gun train, being the same for all ranges. The component A varies with the range in the same general way as does the erosion compensation. Both components A and B vary with the gun train, such variation being proportional to the distance between the gun and the reference point multiplied by the cosine of the angle of train.

It may be assumed that all the after turret guns are located at a common point on the fore and aft centerline of the ship. In the instrument a crank pin 169 is so located on the training angle gear 147 that its radial distance from the center of the training. angle gear 147 represents the distance from the reference point through the common gun position, and the angular position of the crank pin represents the angle of train of the gun from the fore and aft centerline of the ship as read on the scale 148, so that the cosine function of this angle is generated by the rotation of the pin which drives a roller 170 sliding in a training angle carriage 171, mounted to slide in guides 171. By means of a rack 172 this motion is transmitted'to a gear 173 to turn the gear 123 of the rounds fired differential 122, in which such cosine function is added to the function of erosion compensation and the sum thereof is transmitted to the carriage 128 as hereinbefore described.

The compensation arm 105 multiplies the movement of the carriage 128 by the range function represented by the position of the fulcrum 103 and the resultant motion of the compensation carriage 174 represents the range compensation for gun erosion plus component A of the range compensation for horizontal parallax. The movement of the carriage 174 in guides 175 is transmitted through a rack 176 and gears 177 to a gear 178 of the compensation differential 168. Connection between the gears 178 and 167 is effected by means of gears 179 mounted on a spider 180 and meshing with each other and with said gears 178 and 167. The spider 180 is mounted on a shaft 181 which through gears 182 drives the shaft 32 by which is controlled the spider 29 of the differential 28.

Component B of the range correction for horizontal parallax is represented by the position of a rack 183 attached to the carriage 171 and meshing with a sector gear 184 which through a shaft 185 drives a sector 186 meshing with a bevel gear 187 on a shaft 188. The bevel gear 187 is not fixed on the shaft 188 but drives it through a spring 189. Mounted on the shaft 188 is the worm 164 engaging a block 191 to move the rack 163 which drives certain mechanism as hereinbefore described.

The shaft 188 extends to a window in the side of the instrument where there is a Zero setting dial 192 and an index plate 193. By turning the shaft with a screw driver until the index marks are in line the rack 163 may be set in its zero position with reference to the roller path carriage 161. In this operation the gear 187 is held from turning by the sector 186 so that the spring 189 is compressed. When the shaft 188 is released by the screw driver the spring 189 brings the shaft back to its previous position.

As has been shown the compensations for gun erosion plus the component A of the range compensation for horizontal parallax are received by gear 178 and the compensation differential 168 and the roller path compensation plus component B of the range compensation for horizontal parallax is received by gear 167. The quantities received by these gears 178 and 167 are added algebraically in the differential and the spider 180 is turned to a position representing the algebraic sum and drives shaft 181 and through gears 182 the shaft 32 carrying the spider 29 of the dial differential 28.

The lower gear 27 of the dial differential is driven from the gun auxiliary elevating rack 6 as previously explained and the upper gear 31 of the differential takes a position represent'ng an algebraic difference between the actual elevation of the gun and the sum of the various range compensations and through connections hereinbefore described drives stator 14 of the fine selsyn motor 12 and also the fine angle dial 5. Also through connections hereinbefore described the gear 31 serves to turn the stator of the coarse selsyn 11 and the coarse angle reading dial 4. Thus the positions of the angle dials and the selsyn stator are adjusted to represent the algebraic difference between the actual elevation of the gun and the required compensation expressed in terms of gun elevation. The reading of the angle dials will therefore check with the director when the gun has been elevated to the required angle.

As hereinbefore stated the elevation indicator receives a function of range from the shaft 46 outside the case and a function of erosion compensation from the shaft 105', both of said shafts being connected with the erosion .and parallax of adjuster 8. Said erosion and parallax adjuster is provided with a range operating handle 194 on a shaft 195 connected by a suitable train of mechanism including bevel gears 196, 198 and other elements with the shaft 46. Mounted o n the shaft 195 is a gear 200 to drive a gear 201 on the range drum drive shaft 202 carrying a worm 203 meshing with a worm Wheel 204 on a shaft 205 carrying a range drum 206. The function of the range which is to be transmitted to the gun elevation indicator is computed from the formula where C and K are design constants and R is the range plotted spirally on the range drum. The graduations on the range drum 206 run from zero to 75,000 yards, the right hand zero digit being omitted in each number and appearing on a shutter 207 having an opening 208 through which the numbers on the range drum may be observed. On one end of the range drum 206 is a gear 209 which drives a gear 210 on a screw shaft 211 threaded through a portion of the shutter 207. Attached to the sides of the shutter 207 is a ribbon 212 which blots out the remainder of the range drum which would otherwise be visible through a window in the cover. The ribbon 212 forms a loop which encircles the frame of the instrument and as the shutter moves across the drum the ribbon moves with it. To limit the movement of the range drum 206 provision is made of a range stop screw 213 driven from the shaft 202 by means of gears 214. On this screw is a travelling nut 215 provided with stops 216 at opposite sides to engage stops 217 at the extremities of its travel thus providing an effective stop for the range drum, the nut being restrained against rotation by a guide 215.

The erosion and parallax adjuster 'is set for rounds fired by turning the rounds fired operating knob 218 which turns the rounds fired drive shaft 219 and through the intermediate shaft 220, gears 221 and bevel gears 222 drives a rounds 120 fired screw 223. This screw carries a travelling nut 224 provided with a pointer 224 which is driven along a rounds fired scale 225 graduated from 0 to 500, every 10 being marked and every 50 numbered. At the extremities of its travel the 125 pointer 224 engages pins 226 which act as stops. From the shaft 219 the movement of the rounds fired operating knob 218 is transmitted through bevel gears 226a and 227 to shaft 105'.

Since the instruments located at the waist130 guns do not introduce range compensation for horizontal parallax, the lower gear 173 of the rounds red differential 122 is kept locked in the waist gun instruments by the locking plate 227 and the rack 172 is disengaged from gear 173 by being sh'fted to one side as shown in dotted lines.

While the invention has been shown vand described in connection with the elevation of a gun it will be understood that it may beused in connection w th the training of a gun with the corrections required therefor and also that various changes in its details may be made without departing from its principle as defined in the appended claims.

I claim:

1. In a gun-sighting indicator, a zero-reading device settable from a director station, an anglereading device, mutual operating connections between saiddevices, means controlled by .the po- 150 12. In a signal system, a gun director into which movements proportional to values of range and another quantity are required to be introduced by unequal amounts for cooperative action, an adjuster comprising members respectively settable to different extents according to usual values of range and of the other quantity, a connection between the member that is settable according to range and said indicator, including an element permanently associated with said indicator, means actuable by the last mentioned member for breaking said connection when the range setting indicates a range equal to or greater than a predetermined value, and means controlled by the connection breaking means for locking said element when the connection is broken, said member that is settable according to said other quantity being connected to said indicator independently of said connection.

13. In a signal system, a gun direction indicator provided with correctional mechanism having elements respectively displaceable in accordance with functions of range and gun erosion, an adjuster comprising members settable to diierent extents according to the range and, erosion, independently operable connections between the member and element actuated according to range and those operated according to erosion, means for breaking the connection operable according to range rendered effective when the range setting becomes equal to or greater than a predetermined value and operable to restore such connection when the range setting decreases to said predetermined value, and a locking device co-acting with said means to lock and unlock the element that is displaceable according to range when the connection thereto is respectively broken and established.

14. In a signal system, a gun direction indicator provided with mechanism having interconnected portions independently operable to different extents in accordance with functions of range and gun erosion, an adjuster comprising members operably connected respectively to said portions of said mechanism, one of said members being settable according to the range, a connection between said member and the portion of the mechanism of said indicator that is operable in accordance with the range function, means actuable by said member for breaking said connection when the range setting increases through a predetermined value, and means for controlling the connection-breaking means comprising two coaxial discs each having a notch in the periphery thereof, means driven by said settable member to rotate said discs in opposite directions and with such driving ratios that the notches will be brought into alignment when the adjuster setting shows a predetermined range, a rotatable member having a tooth extending across said discs so as to enter said notches when the latter are brought into alignment, and to be rotated by one of said discs so that the tooth will ride out of the notch in the other disc and rest on the circumferences of the discs, and a connection between said rotatable member and the disconnecting means such that the movement of the tooth into the notches will cause an operative movement of the connection-breaking means and the riding of the tooth out of said notches in a direction opposite to its usual direction will cause the connection-breaking means to remain in operated condition.

15. In a signal system, a gun direction. indicator provided with mechanism having interconnected portions independently operable to different extents in accordance with functions of range and gun erosion, an adjuster comprising members one of which is operably connected to the portion of said mechanism that is operable according to the function of erosion, another of said members being settable according to range, an interruptible connection between the last mentioned member and the portion of said mechanism that is operable in accordance with the function of range, means for breaking said interruptible connection when the range setting increases through a predetermined value, and means for locking the connection breaking means until the range setting reaches said predetermined value.

16. In a signal system, a gun direction indicator provided with mechanism having interconnected portions independently operable to different extents in accordance with functions of range and gun erosion, an adjuster comprising members one of which is operably connected to the portion of said mechanism that is operable according to the function of erosion, another of said members being settable according to range, a breakable connection between said last mentioned member and the portion of said mechanism that is operable in accordance with the function of range, a device comprising variously operated elements and operating means controlled thereby effective when said elements are in predetermined correlation to break said last mentioned connection, and means co-acting with said operating means to lock said device out of action until the adjuster is actuated to an extent to bring its range reading to a predetermined value.

17. In a signal system, a gun direction indicator operable proportionally to functions of range and another quantity, an adjuster comprising members one of which is connected to said indicator to actuate the same in accordance with said other'quantity, another of said members being settable according to range and to a different extent than the iirst mentioned member, a breakable connection between said member that is settable according to range and said indicator, means for breaking said connection and means for preventing the breaking of said connection when the range indication is less than a predetermined value.

18. In an elevation indicator for a gun, means to adjust the indications thereof comprising means to generate a cosine function of the angle of train from a reference line, means to supply a. function of erosion compensation, means to combine said functions, means to multiply the result of such combination by a range function, and means to generate said range function com prising Aa cam having a spiral groove and a follower projecting into said groove to be actuated by the cam.

19. In a gun elevation indicator, means to adjust the indications thereof comprising means to generate a cosine function of the angle of train from the line between the gun and the director station, means to supply a function of erosion compensation, means to combine said functions and position a parallax and erosion carriage, and means to multiply the result of such combination by a range function to obtain a correction to be applied to the elevation indicator, said multiplying means comprising a range carriage, a rangecarriage-actuating lever having a cam follower,

sition of a gun, mechanism for determining corrections for the guns position, and combining means operable by said controlled means and mechanism and operably connected to said mutual connections, said zero-reading means being operable to read zero when the gun is properly positioned and the angle-reading device to read in accordance with the angle between the direction of the gun and its reference position, both said devices co-acting to indicate the algebraic difference between the actual position of the gun and its required compensation.

2. In a signal system for controlling the aiming of a gun, an elevation indicator adjacent the gun to be aimed and comprising an element of which the reading is set from a director station, mechanical means controlled by the gun for setting said element to zero when the gun is brought to the proper elevation, and means operatively connected to said mechanical means for correcting the indicator setting including means to compensate for the elevation error due to the range component of horizontal parallax.

3. In an elevation indicator for a gun, means to introduce corrections comprising means for generating an elevation function for horizontal parallax including means to generate a cosine function of the angle of train from the line between the gun and a director station, means for generating an erosion function, and means for correcting the elevation reading including means for combining said functions for horizontal parallax and erosion to obtain a correction to be applied to the elevation indicator.

4. In an elevation indicator for a gun, means to introduce corrections comprising means for generating an elevation function for horizontal parallax, means for generating an erosion function, means for generating a required range function, said means including a device operable in accordance with a range value and provided with automatically responsive means to modify the same to effect the required range function, and means for combining said functions to obtain a correction to be applied to the elevation indicator.

5. In a gun elevation indicator, means to adjust the indications thereof comprising means to generate a cosine function of the angle of train from the line between the gun and the direction station, means to supply a function of erosion compensation, means to combine said functions, and means to multiply the result of such combination by a range function.

6. In a gun elevation indicator, means to generate a function of range compensation for horizontal parallax including a member rotatable in accordance with the training of a gun, means to generate a correction for roller path inclination comprising an element adjustable angularly and radially of said member in accordance with evaluations of a particular roller path inclination and the high point of the roller path, and means to maintain such adjustments, whereby the element is caused to generate a compensation for the roller path.

'7. In a gun elevation indicator, means to adjust the indications thereof comprising a member angularly displaceable about an axis, an element fixed on said member at a radial distance from said axis representative of the line between a gun and a director station, means operable in accordance with the training of the gun to displace said member and element to `cause the latter to generate a cosine function GCG of the angle of train from the line between the gun and the director station, means to generate an erosion function, and a differential comprising an element to be actuated by the cosinefunction-generating means, a second element actuated by the erosion-function-generating means and a third member to be driven by the other two elements.

8. In a gun elevation indicator, means to adjust the indications thereof comprising means to generate a cosine function of the angle of train from the line between the gun and the director station, means to supply a function of erosion compensation, means to combine said functions, and means to multiply the result of such combination by a range function to obtain a correction to be applied to the elevation indicator, said multiplying means comprising a range carriage, a cam operable in accordance with a function of range to modify the same, a following member controlled by said cam, and a ratio-establishing element of said multiplying means settable by said member.

9. In a signal system, a gun direction indicator into which movements proportional to values of range and another quantity are required to be introduced by unequal amounts for cooperative action, an adjuster comprising members respectively settable to different extents according to useful values of the range and of the other quantity, a connection between the member that is settable according to range and said indicator, and means actuable by the last mentioned member for breaking said connection when the range setting increases to a predetermined value, said member that is settable according to said other quantity being operable after the breaking of said connection.

10. In a signal system, a gun direction indicator into which movements proportional to values of range and another quantity are required to be introduced by unequal amounts for cooperative action, an adjuster comprising members respectively settable to different extents according to useful values of the range and of the other quantity, a connection between the member that is settable according to range and said indicator, and reversely operable means actuable by the last mentioned member for breaking said connection when the range setting increases through a predetermined value and for restoring said connection when the range setting decreases through said predetermined value, said member that is settable according to said other quantity being operable after the breaking of said connection.

11. In a signal system, a gun direction indicator into which movements proportional to values of range and another quantity are required to be introduced by unequal amounts for cooperative action, an adjuster comprising members respectively settable to different extents according to useful values of the range and of the other quantity, a connection between the member that is settable according to range and said indicator, including a driven element permanently associated with said indicator, means actuable by the last mentioned member for breaking said connection when the range setting indicates a range equal to or greater than a predetermined value, and a locking device operable responsively to said means to lock said element when said connection is broken, said member that is settable according to said other quantity being operable after the breaking of. said connection.

im mom Hemus Mm;

tain quantity and a second member for actuation in accordance with a function of a diiferent quantity when it is required, means for generating the function of the last named quantity, a driving connection between the last named means and said second member subject to disconnection therebetween, and means for locking said second member out of action during such disconnection.

HANNIBAL C. FORD. 

